Backend thumping and thudding every time I hit a bump

This started last night, every little divot or bump in the road is causing the car to bounce and shake, frequently with a loud thump/thud noise coming from the backend. I’m guessing it’s the shocks/struts, but I don’t know, and would really like to identify the problem before I drop a few hunded bucks into fixing something that isn’t broken. I’m sorry for the lack of information here, but I’m not sure what information would be useful. I’ll gladly answer any questions that would help with diagnosing this problem. Thanks in advance.